title: Partial A1 adenosine receptor agonist regulates cardiac substrate utilization in insulin-resistant rats in vivo.
abstract: Reducing the availability and uptake of fatty acids is a plausible pharmaceutical target to ameliorate glucose intolerance and insulin resistance. CVT-3619 [2-{6-[((1R,2R)-2-hydroxycyclopentyl) amino]purin-9-yl(4S,5S,2R,3R)-5-[(2-fluorophenylthio)methyl]oxolane-3,4-diol] is a partial A(1) adenosine receptor agonist with antilipolytic properties. Aims of the present study were to examine the acute effects of CVT-3619 on whole-body and cardiac glucose and fatty acid kinetics in vivo in normal and diet-induced insulin-resistant rats. Male Sprague-Dawley rats were fed either a chow (CH) or high-fat (HF) diet for 4 weeks. Catheters were then chronically implanted in the carotid artery and jugular vein for sampling and infusions, respectively. After 5 days of recovery, fasted animals (10 h) received either saline or CVT-3619 (0.4 mg/kg bolus + 1 mg/kg/h). Indices of glucose and fatty acid utilization were obtained by the administration of 2-deoxy[(14)C]glucose and [9,10-(3)H]-(R)-2-bromopalmitate. HF feeding resulted in elevated, fasting insulin and free fatty acid (FFA) levels compared with CH. CVT-3619 caused a 64 and 86% reduction of FFA and insulin in HF (p < 0.05) but less (N.S.) in CH diet-fed animals. In HF diet-fed rats, CVT-3619 increased whole-body glucose clearance with no change in fatty acid kinetics. Likewise, analysis of cardiac tissue metabolism showed that CVT-3619 caused an increased glucose but not fatty acid clearance in HF-fed animals. Results show that the acute administration of CVT-3619 lowers circulating fatty acid levels, leading to improved whole-body and cardiac glucose clearance in a model of diet-induced insulin resistance. As such, CVT-3619 may be a treatment option for the restoration of substrate balance in the insulin-resistant heart.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta, Canada. jshearer@ucalgary.ca
authors.forename: Jane
authors.initials: J
authors.lastname: Shearer
authors.forename: David L
authors.initials: DL
authors.lastname: Severson
authors.forename: Lin
authors.initials: L
authors.lastname: Su
authors.forename: Luiz
authors.initials: L
authors.lastname: Belardinelli
authors.forename: Arvinder K
authors.initials: AK
authors.lastname: Dhalla
mesh_terms: D000241:Adenosine / Q000031:analogs & derivatives* / Q000494:pharmacology; D058907:Adenosine A1 Receptor Agonists; D000818:Animals; D002339:Carotid Arteries; D004041:Dietary Fats; D005230:Fatty Acids, Nonesterified / Q000097:blood / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects; D005947:Glucose / Q000378:metabolism*; D006321:Heart / Q000187:drug effects / Q000502:physiology; D007328:Insulin / Q000502:physiology; D007333:Insulin Resistance / Q000502:physiology*; D007601:Jugular Veins / Q000502:physiology; D008066:Lipolysis; D008297:Male; D023421:Models, Animal; D009206:Myocardium / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: C510789:2-(6-((2-hydroxycyclopentyl)amino)purin-9-yl)-5-((2-fluorophenylthio)methyl)oxolane-3,4-diol; D058907:Adenosine A1 Receptor Agonists; D004041:Dietary Fats; D005230:Fatty Acids, Nonesterified; D007328:Insulin; D005947:Glucose; D000241:Adenosine